Bronchiolitis obliterans (BO) after lung transplantation prevents a satisfactory prognosis, and recent studies suggested that interleukin-10 (IL-10) gene transfer to distant organs could inhibit BO in rodent models. Although delivery of the therapeutic gene to a local airway would be favored to minimize systemic effects, current limitations include lower gene transfer efficiency to airway epithelium. As recombinant Sendai virus (SeV) can produce dramatically efficient gene transfer to airway epithelium, we determined if SeV-mediated IL-10 gene transfer to the local airway would inhibit bronchial fibrous obliteration in murine tracheal allografts. Administration of cyclosporine A (CsA) significantly promoted not only recovery of the injured airway epithelium but also SeV-mediated IL-10 expression (CsA- versus CsA+ =228+/-78 versus 3627+/-1372 pg/graft with 5 x 10(7) pfu), thereby suggesting the requirement of epithelia for efficient gene transfer. Even at the highest expression, no significant leakage of IL-10 was evident in the systemic circulation, and the induction of interferon-gamma was completely diminished on day 7 by IL-10 gene transfer. As a result, luminal loss was significantly prevented in allografts treated with SeV-IL-10 (luminal opening, all control groups: 0% respectively, and SeV-IL-10 5 x 10(7) pfu: 25.7+/-10.5%), an effect that was enhanced by short-term CsA treatment (SeV-IL-10 5 x 10(7) pfu with CsA: 63.7+/-12.7%). We propose that SeV is a useful vector that can target airway epithelium to prevent BO avoiding putative systemic effect.